Earth Almost Put on Impact Alert - Interesting!!

[tanichols]

All,

Just came across this story:
http://news.bbc.co.uk/2/hi/science/nature/3517319.stm

The irony of it all is quite interesting.

Imagine Bush's NASA Vision Speech INSTEAD being about a looming Asteroid
Impact!

I was strapped to my seat reading this! We get these stories all the time, it just shows how many objects are out there that we don't have the capability to track or find until they're right at our front door. As many have said the one that hits us we may never know nothing about till a day or so before...

And the interesting thing is I know the guy that contemplated making the call to Bush! I worked in the same office at Southwest Research Institute's Department of Space Studies with Dr. Chapman when I was working on the New Horizons Pluto Mission there 2 summers ago.. I bet it was hectic there a few weeks ago, I wonder if any "It's the End of the World" signs were posted anywhere? Can you imagine going home to your family when they still weren't sure about this and were contemplating making the call? I'm pretty sure it was hush hush, but just imagine if you knew before they figured out we were in the clear. I wonder if any of them cleaned out their Savings? :)

Regards,
Ted A. Nichols II
President- Astronomical Society of Harrisburg
www.astrohbg.org

[Littlemews]

There is one around 1930s, I think its 1923 or smething, a group of ppls they saw the comet Halley and they think its then end of the world, then drink Posion commit suicide ;) I am not sure when and where, but this is real...

A giant asteroid is heading for Earth and could hit in 2014 :huh: is this real?
http://www.cnn.com/2003/TECH/space/09/02/a.../asteroid.reut/ (http://www.cnn.com/2003/TECH/space/09/02/asteroid.reut/)

[Duane]

And 2004 AS1? It turned out to be bigger than anyone had thought - about 500m wide. It eventually passed the Earth at a distance of about 12 million km - 32 times the Earth-Moon distance, posing no danger to us whatsoever.



Hmmm--what about next time it comes around.......

[NasaBoy]

Still, you just know an Asteroid is gonna hit sometime in the future.....and im talking dinosaur killer size....................You are on the beach, looking at the sky, then a 2 km Asteroid comes falling with little baby Asteroids falling with it....Just picture it, a very scary image of you first hand seeing a giant Asteroid hitting the Earth. :o

[DippyHippy]

Littlemews, I wouldn't worry about that one, that's long been proven to miss the Earth...

As for this story, it's quite fascinating. $10 says it'll get made into a movie-of-the-week LOL Seriously, it does highlight the critical fact that there are no set guidelines for this kind of emergency.

Personally, I find it alarming that President Bush should be the first to know - it could have been a global catastrophe and he's just the President of the United Stated (and not, I hasten to add, "the leader of the free world" as the President is often labelled. I live in England, he's not my ruler and I wasn't given a vote in the US election!!) I'd have thought notifying the UN would have been far more sensible.

Lastly, I was lucky enough to interview Brian Marsden a few years ago on the telephone (for a piece about NEO's - it's somewhere here in UT) and he himself said there are no guidelines for notifying the world and that probably the most prudent action would be to first notify the UN.

[TheThorn]

There's something in that article that really bothers me.

This "Steven Chesley, a researcher at Nasa's Jet Propulsion Laboratory" guy who sent out the e-mail that caused the flap said in the e-mail that there was a 25% chance that this asteroid would hit the earth in the next couple of days. That's a pretty specific claim, which is easy to understand mathematically.

To make that claim in a meaningful way, he must have calculated a trajectory for the asteroid, and calculated the uncertainty around that trajectory, and that the earth was inside the limits of that uncertainty, and that the cross section of the earth was 25% of the cross section of the uncertainty around the trajectory. Since the earth is about 13,000 km in diameter, that means that the uncertainty he had calculated for the path of the asteroid was 26,000 miles in diameter (area is proportional to square of diameter).

He was claiming that he knew that the thing would miss us by 13,000 km or less. Either that or he was blowing smoke out his ***.

How anyone could come up with an orbit that precise based on only 4 observations would be a question that should have been asked at the time (and apparently some people did raise that sort of doubt, because they did nothing).

The damn thing missed by 12,000,000 km. So the guy was blowing smoke out his ***. And almost caused extreme worldwide alarm unnecessarily.

Crying "wolf" on something this significant, which might cause people to ignore a future real warning, that would be criminal.

I wonder if anyone is taking Mr. Chesley to task for this indiscretion.

[Dave Mitsky]

This is another case of something being blown grossly out of proportion. See what Phil Plait has to say about it at http://www.badastronomy.com/bad/misc/c2c_f...04.html#2004AS1 (http://www.badastronomy.com/bad/misc/c2c_feb262004.html#2004AS1)

Dave Mitsky

[damienpaul]

There seems to be an ever increasing amount of these scare campaigns so to speak, or is it just me.

Perhaps some kind of standards need to be established to curb this hot air peoduction.

[Matthew]

Its the crying wolf syndrome. Most people disregard asteroid threats these days, because so many have been wrong. There should be a main center where all warnings are assessed for their validity, and release them to the public as appropriete.

Anyway, we would never see the HIGH risk alerts, governments, Nasa, and militaries would keep that information secrtet as not to cause a mass panic. Which would occur.

[NasaBoy]

Yeah, but if we the public didn't know about the high risk alerts, wouldn't that be bad? I mean don't get me wrong, I know we don't want a mass panic on our hands, but shouldn't we know so we can prepare or whatever? I mean what if you were at your relative's house and then you had to leave? If you knew that a killer Asteroid was heading right for Earth and was gonna hit in the next 48 hours or whatever you would stay as long as possible with the ones you love just before you die. I mean wouldn't you be confused if you saw a 120 km wide Asteroid falling from the sky, then the next thing you know your a pile of dust and the Earth is the same and the sky stays black for years, you not knowing this was going to happen? I know they don't want everyone crazy, but wouldn't you want to know if a huge Asteroid or Comet(doubt it)was going to hit Earth very soon? Im not trying to start problems im just saying lets be realistic here. I would want to know if the Earth was going to become the victim of Comet Shoemaker Levy 9 Two in 3 or 4 days. Heck, maybe a month or a year.

[DippyHippy]

Nasaboy, I don't think anyone would disagree that the public has a right to know if it's known the asteroid *will* hit - but there's absolutely no point in alerting the public to an asteroid that only *might* hit. Can you imagine the panic that would ensue?

As for the true story of what happened, I think the guy on the radio who kicked this whole thing off should be sued!!! I know if I were one of the astronomers concerned, I'd be extremely angry and would be issuing statements through my lawyers!!

[TheThorn]

This incident is very interesting. The link that Dave provided is instructive, and some of the links off it lead to even more enlightening reading. The thread on the YahooGroups’ mpml list is especially interesting. Reading it all (about 100 posts on the subject in 2 days as it happened) is time consuming, but gives you a much better feel for what went on here. Let me try to give my understanding of it:

On Jan. 13th LINEAR discovered an asteroid that they provisionally named AL00667. They had a total of 4 observations of the object over a one hour period. That's not much to go on, but the Minor Planet Centre (MPC) used these four observations to calculate an orbit for the object and posted an ephemeris (a prediction of it’s future positions in the sky for the next few days) for it on their web site, without comment. Some amateurs quickly noticed that if the posted ephemeris was exact, the object would collide with the earth in about 36 hours. Considerable discussion ensued.

A few hours later, another amateur observed the location that the object should have been in if the posted ephemeris was accurate, and did not find the object. This confirmed that it was NOT on a collision course with Earth. Professional observatories that work on this stuff were clouded out for the moment. Another amateur also could not locate the object anywhere near the posted predicted location. The next evening LINEAR recovered the object, at a considerable distance from it’s predicted location, and the MPC confirmed that it would not impact earth. Considerable more discussion ensued.

The whole thing was over in less than 24 hours. The press picked up the story over a month later (how’s THAT for timely?) and blew it all out of proportion.

The “problem” (if there is one) is two fold. 1) the MPC posted an orbit that implied an imminent impact without comment. 2) Some people misunderstood just how inaccurate such an orbit can be.

No doubt the reason that the MPC would post such an orbit without comment is that they understand that any orbit based on an observational arc 1 hour long is pretty much useless for any purpose other than giving a starting point to try to recover the object for further observations. And they probably expect that anyone reading their site would also understand.

Let me give an analogy: You are a pro ball outfielder. You’re looking up, with your eyes closed. You’re allowed to open your eyes for 1/10 of a second, and you glimpse something moving in the sky above you. To the best of your well trained professional ability, you estimate it’s trajectory based on that brief arc, and conclude that it appears to be a fly ball heading directly for a landing in your glove four seconds from now. Three seconds later, they allow you another peek at it. Would you be surprised to discover that it was actually an airliner heading for a landing at an airport 100 miles away? Sounds like a huge mistake, but it’s understandable – based on the limited data you had to start with, and a couple of reasonable assumptions about size and distance, you made your best estimate. Given an extended arc of observation, you could refine that estimate.

Scale that example up by a factor of a couple of thousand or more, any you have exactly the situation that happened here.

As for the scientists keeping imminent impacts secret, this particular episode demonstrates that the exact opposite is true. They freely posted an imminent potential impactor as if it were nothing unusual at all! The original orbit was not for an interesting near miss, it was for a Direct Hit and they threw it out on the web without even commenting on it! What if that amateur had found the object right where it was expected to be, and confirmed that it was going to impact in less than 24 hours? Do you think the MPC would have been able to get that cat back into the bag? That mpml list had been discussing it for hours by then, and that list has 866 members. Try to hush that one up? Good luck.

The thread at YahooGroups starts with
this post (http://groups.yahoo.com/group/mpml/message/11316). About 48 hours (and 100 posts) later, this very good post (http://groups.yahoo.com/group/mpml/message/11444) pretty much explained the reasons that a preliminary orbit could be so much in error, and the kind of assumptions that they had to make to come up with any orbit at all. Worth the read.

[Fraser]

Thanks for the analysis, this is great.

[Victoria]

Interesting the differences of crater the asteroids leave on impact. After viewing a great site referred by devilmech on Venus...I came across more than a few graet pics as well as comparisons on craters. 4 different atmospheres, 4 different holes...1 in particular was noticably seperate. Venus. B)

[damienpaul]

It is remarkable indeed how the atmosphere and the surface structures of the planets can have an effect of the type and the durability of craters.

[Victoria]

After considerable thought, my admiration of each rises. Every asteroid that landed and made its mark is 'remarkable' and for every moon, planet... still floating B) :) . Gotta love tech these days. Thanks for the great pics!!!

[NasaBoy]

Dippy, that was what I meant in a very long speech. The public has a right to know if a Asteroid is 100% sure to hit.